The immediate postsurgical fitting of a prosthesis has many advantages. These include accelerated healing and less postsurgical pain, prevention of contractures, fewer psychological problems, and the return of the patient to work or home much earlier. Some prefer the immediate application of a rigid plaster dressing snugly over the sterile dressings of the below-the-knee amputation before the patient leaves the operating room. A socket is secured into its base, and an adjustable pylon can be immediately fitted for ambulation within a few days after surgery. After the sutures have been removed and wound healing has been evaluated, a new cast-socket is reapplied. The original prosthetic unit is replaced and realigned. After the second cast-socket has been worn for 10 days, a new cast can be taken for the permanent prosthesis, which may be fitted within 30 days. Early socket changes are necessitated by shrinkage that which occurs in spite of immediate fitting. A less costly technique is use of the “air leg,” an air bag allowing the surgeon to view the stump postoperatively but permitting the patient to bear weight on it. If the rigid dressing is not used, the usual time of fitting is 8 to 10 weeks for above-knee and 10 to 12 weeks for below-knee amputations. The more distal the amputation, the longer the postoperative period prior to fitting because of the accumulation of edema.